The present invention relates generally to imaging systems and more particularly to computed tomography. A computed tomography or CT scan is a method of taking pictures of the inside of the body using an ultra-thin x-ray beam. As the x-ray beam passes through the body, it is absorbed by bones, tissues and fluid within the body, thereby varying resultant beam intensity. The intensity of the x-ray beam emerging from the body is measured by a device that converts x-ray beam data into a detailed picture.
Multi-slice CT scanners are special CT systems equipped with a multiple-row detector array rather than a single-row detector array. This allows for simultaneous scan of multiple slices at different locations.
A typical CT scanner includes a gantry having an annular frame for rotatably supporting an annular disk about a rotation or scanning axis of the scanner. The disk includes a central opening large enough to receive a patient extending along the scanning axis, and the disk is rotated about the patient during a scanning procedure. An x-ray tube is positioned on the disk diametrically across the central opening from an array of x-ray detectors. As the disk is rotated, the x-ray tube projects a beam of energy, or x-rays, along a scan plane, through the patient, and to the detector array. By rotating the x-ray source about the scanning axis and relative to the patient, x-rays are projected through the patient from many different directions. An image of the scanned portion of the patient is then constructed from data provided by the detector array using a scanner computer.
A disadvantage of the aforementioned system is that acquiring further information requires either an increased dose of x-rays or an increased number of x-ray scans.
A further disadvantage of the aforementioned system is that back-scatter radiation is not utilized to obtain an increase amount of information about the patient. Back-scattering is the deflection of radiation or particles by scattering through angles greater than 90° with reference to the original direction of travel.
The disadvantages associated with current, CT systems have made it apparent that a new technique for CT scanning and data transfer is needed. The new technique should substantially increase information acquired from each patient and should also utilize back-scatter x-rays as a source of information. The present invention is directed to these ends.